Method and apparatus for detecting tire information mark

Abstract

In case of detecting tire information marks engraved in a side wall portion of tire in the form of protrusion or recess, width and inner diameter of tire are detected to provide a tire size signal, after a first camera head is driven into a given position in accordance with the tire side signal, an identification mark engraved in the size wall portion of tire is optically detected by the first camera head to derive a position signal, and after a second camera head is driven into a given position in accordance with the position signal, the tire information marks are optically detected by the second camera head to derive a tire information signal. In this manner, the tire information marks can be detected in a rapid and accurate manner.

What is claimed is: 
     
       1. An apparatus for optically detecting tire information marks formed on a side wall portion of tire in the form of a protrusion or recess, comprising first detecting means for detecting width and inner diameter of tire to derive a tire size signal;   second detecting means comprising a detector head for detecting an identification mark provided on the side wall portion of tire separately from the tire information marks, and means for positioning said detector head in accordance with the tire size signal and for rotating relatively the detector and tire to derive a position signal representing both circumferential and radial positions of the information marks; and   third detecting means comprising a camera head for picking up the tire information marks and, means for positioning the camera head in accordance with the position signal.   
     
     
       2. An apparatus according to claim 1, further comprising means for feeding the tire along a path along which said first, second and third detecting means are arranged in this order. 
     
     
       3. An apparatus according to claim 1 wherein said camera head of the second detecting means comprises a linear image sensor having a plurality of light receiving elements aligned in the radial direction of the tire. 
     
     
       4. An apparatus according to claim 1, wherein said camera head of the third detecting means comprises a two dimensional image sensor which picks up an image of the tire information marks, while the camera head and tire are not relatively moved. 
     
     
       5. An apparatus according to claim 1, wherein said detector head of the second detecting means is formed by a camera head for optically picking up the identification mark which is engraved in the side wall portion of tire in the form of protrusion or recess. 
     
     
       6. An apparatus according to claim 5 wherein said camera head of the second detecting means is arranged movably in width and radial directions of the tire and rotatable about an axis. 
     
     
       7. An apparatus according to claim 6, wherein said second detecting means further comprising means for positioning the tire with respect to the camera head such that a tire axis is aligned with said axis about which the camera head is rotatable. 
     
     
       8. A tire for use in a vehicle comprising; a main body including head portion, side wall portion and tread portion, tire information marks engraved in the side wall portion in the form of a protrusion of a recess, and an identification mark engraved in the side wall portion in the form of a protrusion or a recess separated from the tire information marks, said identification mark being formed by a bar code having a plurality of elongated elements which are extended in a circumferential direction of the tire and are aligned in the radial direction of the tire, whereby said identification mark and said tire information marks are provided on the same circle. 
     
     
       9. A tire according to claim 8 wherein said identification and tire information marks are formed by protrusions having a triangular cross section whose apex angle is set to 40°-140°, preferably 55°-110°, whose height is set to 0.4-1.4 mm, preferably 0.4-0.8 mm, and whose base width is set to 0.4-1.0 mm, preferably 0.4-0.8 mm. 
     
     
       10. A method of detecting tire information marks provided on a side wall portions of tire in the form of a protrusion or a recess comprising the steps of: detecting an identification mark provided on the side wall portion of tire separately from the tire information marks, at a fist detecting stage with the aid of a first detector head to derive a position signal representing both circumferential and radial directions of the information marks;   transporting the tire from said first detecting position into a second detecting position, while the attitude of the tire is kept substantially unchanged;   positioning at least in circumferential and radial directions of the tire a second detector head provided at the second detecting position in accordance with said position signal; and   detecting the tire information marks with the aid of said detector head.   
     
     
       11. A method according to claim 10 wherein prior to the detection of the identification mark, width and inner diameter of tire are detected to derive a tire size signal, and said first detector head for detecting the identification mark is positioned with respect to the tire in accordance with the detected tire size signal. 
     
     
       12. A method according to claim 11, wherein said identification mark is formed by a bar code mark consisting of a plurality of elongated elements which are extended in the circumferential direction of tire and are aligned in the radial direction of tire, and the identification mark is optically detected by the second head comprising a linear image sensor including a plurality of light receiving elements aligned in the radial direction of tire. 
     
     
       13. A method according to claim 11, wherein said second detector head is positioned also in a direction substantially perpendicular to said circumferential and radial directions in accordance with said tire size signal. 
     
     
       14. A tire according to claim 8, wherein said identification mark is formed by an odd number of elongated elements which have substantially same length in the circumferential direction of tire. 
     
     
       15. A number according to claim 14, wherein said odd number of elongated elements are separated substantially equidistantly from each other in the radial direction of tire. 
     
     
       16. A method according to claim 10 wherein said tire information marks are engraved in the side wall portion of tire in the form of a protrusion a or recess, and the tire information marks are optically detected by the second detector head including an image sensor. 
     
     
       17. A method according to claim 16 wherein said indentification mark is engraved in the side wall portion of tire in the form of a protrusion or recess, and the identification mark is optically detected by the first detector head including an image sensor.